/Engine/Source/Runtime/Engine/Classes/Kismet/KismetSystemLibrary.h
Returns the current platform time in seconds. Not coupled to any gameplay or other containerization logic - this function is useful for timing execution time or timestamping data. Marked as callable rather than pure because implicit evaluation may be confusing, both for blueprint authors and blueprint readers. For implicit execution simply wrap it in a blueprint pure function.
static double GetPlatformTime_Seconds()